Hairdressers with dermatitis should always be patch tested regardless of atopy status.

Background: Allergic contact dermatitis is common in hairdressers because of their exposure to chemicals used in hair dyes and permanent wave solutions. Atopic individuals are known to have a higher prevalence of leaving the profession due to morbidity associated with hand eczema.
Objectives: To assess which chemicals are responsible for allergic contact dermatitis in hairdressers and whether the prevalence is the same according to atopy status.
Methods: A total of 729 hairdressers who had been patch tested were retrospectively identified. Allergic reactions to relevant allergens from the extended European baseline series and hairdressing series were analysed against history of atopic eczema.
Results: Of the total, 29.9% of patients had a current or past history of atopic eczema. The most frequent positive allergens from the European baseline series were nickel sulfate (32.1%) and p-phenylenediamine (19.0%) and from the hairdressing series were glyceryl monothioglycolate (21.4%) and ammonium persulfate (10.6%). There was no significant difference between people with or without a history of atopic eczema, except for fragrance mix I and nickel sulfate.
Conclusions: We present findings from the largest cohort of hairdressers patch tested from a single centre. It is necessary to patch test hairdressers with dermatitis, regardless of a history of atopy. Strategies to reduce prevalence of allergic contact dermatitis are required.